Integral hub for reversible pitch propellers



Sept. 4, 1934- w 5 HOOVER 1,972,487

INTEGRAL HUB FOR REVERSIBLE PITCH PROPELLERS Filed Dec. 2, 1931 3 Sheets-Sheet 1 INVENTOR. m 5.

A TTORNE Y.

'Sept. 4, 1934'. w. s. HOOVER 1,972,487

INTEGRAL HUB FOX 1 REVERSIBLE PITCH PROPELLERS I Filed Dec. 2, 1931 I 3 Sheets-Sheet 2 mvmvrox. 77% s. W

A TTORNE Y.

p 4, 1934- w. s. HOOVER 1,972,487

INTEGRAL HUB FOR REVERSIBLE PITCH PROPELLERS Filed Dec. 2, 1931 3 Sheets-Sheet 3 ATTORNEYS.

Patented Sept. 4, 1934 PATENT OFFICE INTEGRAL HUB FOR REVERSIBLE PITCH PROPELLERS Walter S. Hoover, Girard, Pa., assignor of onehalf to Patrick H. Crow, Meadville, Pa.

Application December 2, 1931, Serial No,,578,514 6 Claims. (01. ire-113V This invention relates to improvements in propeller hubs, more particularly to hubs for propellers of the reversible pitch type.

It is among the objects of the invention to I provide a hub construction of a unitary onepiece casting to render it adaptable to the stresses I to which reversible pitch propeller hubs are subjected and which shall be provided with simple and eflicient means for assembling theblade 10 members therein.

- A further object of the invention is the provision of means for directing the scavenged gases from the engine motivating the propeller through the hub and into the hollow propeller blades II from which the gases are vented through slots" provided adjacent the blade tips, such means being formed'integrally with the hub structure. A further object of the invention is the prov visionof reversible pitch propeller hubs of inte- 80 gral construction wherein the pitch adjusting mechanism is contained within a relatively compact space and which is designed to facilitate the assembly of the hub on the engine shaft and the assembly and adjustment of the blade roots in the hub structure. r A funther object the invention is the provision of a hub structure of'the above designated character which shall comprise a minimum number of operating parts designed to facilitate their assembly and to provide access to the interior of the hub without dismembering the entire hub element and without dismounting the same from the engine shaft. 4

These and other objects of the invention will hereof' and in which like reference characters designate like parts and in which Figure 1 is a :having gear-teeth 19 are disposed will the hub cross sectional view taken longitudinally of a propeller hub embo ying the principles of this invention; Figure 2, a cross sectional view taken along the lines 11-11 of Figure 1; Figure 3, a cross sectional view taken along the lines 'III-1I[ of Figure 1; Figure4, a top plan'view;v and Figure 5, a front elevation of the hub structure.

With reference to the several, figures of the drawings, the structure therein illustrated comprises an integral casting generally designated 50 which'is provided with a splined socket 2 for receiving the end of an engine shaft 3 of Figure 2, the splined end of the shaft interacting with the spline surfaces 2 of the hub. The shaft 3 is of C hollow construction and is assembled in the hub become'more apparent from a consideration of the accompanying drawings constituting a part by the reference character 1 the rear end of to interact with the teeth oi 9,. beveled gear by means of a ring 4 and a tapered wedge ring 5, Figure 2.

By means of the integral casting, the load is distributed uniformly over the entire hub struc ture and the front face of the hub is of sufficient proportion to receive the blade adjusting mechanism without rendering the construction of the hub unduly large and heavy. I

A pair of hub sockets having interiorly threaded surfaces 6 and 7 are provided in alinement transversely to the axis of the shaft socket 2 and are adapted to receive hub sleeves 8 and 9, respectively, the sleeves being provided with flanges 8 and 9'- having exterior threads which are adapted to interact with thethreads s and 7 of the hub casting.

The flanged ends of the hub sleeves 8 and 9 are provided with grooves 10 constituting races for anti-friction ball-bearings 11, these races constituting abutments against which the thrust of 75 the propeller blades react.

Disposed within the hub sleeves 8 and 9 are sleeve members 12 which are adapted to receive the anchorage roots 13 of the propeller blades, a portion of which is shown in Figure 1, the sleeves 12 being secured in the hub sleeves 8 and 9 by means of wedge rings 14, each having'a tapered body portion 15 which engages the complementary shaped surface of the sleeves 12, and the rings 14 are provided with screw threads 10 which engage threads formed in the sleeves 12.

The wedge rings 14 are provided with notches 17 for engagement with a spanner wrench or gripping member by means of which the ring 14 is screwed onto the thread 16' thereby contracting the outer ends of the tapered lock sleeve 12 to firmly grip the blade roots. A plurality of split beveled gears, or annuli, 18

structure-against ball races 20 which cooperate with the races 10 of the members 8 and.9,- the beveled gears being provided with beveled edges 21 and grooves 22 and 23, forming a structure which is adapted to interact with similar tongues and grooves constituting anchorage abutments around the ball races 20 to prevent binding 'of the 195 rotating parts with the hub portion and to enable the bearing race to adjust itself in relation to the balls.

The teeth 19 of the split snhmi 1a are which is the actuating member of the pitch controlling mechanism. Gear. wheel 25 is mounted on a splined end 26 of a hub that extends from a hydraulic unit 27, the member 27 being an angularly rotatable member or piston contained within a casing 28. A torsion spring 29 is provided with one of its ends secured to the casing 28 and its other end 30 secured to the beveled gear 25. So long as no force is applied to the angularly movable member 27, the beveled gear 25 will be in a normal position to which it is biased by the torsion spring 29 and which is the normal advance setting position of the propeller pitch angle.

. With reference to Figures 2 and 3 of the drawings, the rear of the hub is shown as provided with an annular chamber 32, into which the exhaust gases of the engine are conducted and from which they pass through conduits 33 and 34 to the interior of the hub where they are routed through the hollow blades to reaction vents, (not shown), in the blade tip.

The hydraulic unit 27 is operated by fluid pressure conducted through ports 35 and 36 to which conduits 3'7 and 38 are connected. The conduits pass through the hollow interior of the engine shaft to a control valve, the construction of which is disclosed in a copending application Serial Number 578,513 filed December 2, 1931.

As shown in Figure 3 of the drawings, the beveled gear members 19 are split members comprising the half sections 39 and 40 which have splined interiors which interact with the splined surfaces of the lock sleeves 12.

' With reference to the assembly of the hub, the hub casting 1 is first secured to the engine shaft 3 in the manner shown in Figure 2, and for this assembly the hydraulic control unit 2'? and the beveled gear 25 are removed. The beveled gears 19 may likewise be removed from the hub so that suflicient space is provided to furnish access for the assembly of the nut 4 on the end of the engine shaft.

After, the hub has been mounted on the end of the shaft, the beveled gear annuli 19 are disposed around the anchorage abutments of the blade roots 13 in the manner shown on the bottom of Figure 1 of the drawings, and after being so as-' sembled, the sleeves 12 are passed over the annuli in the manner shown in Figure 3. The wedge rings 14 are then screwed on the sleeves 12 to secure the blade roots, and the hub elements 8 are passed over the sleeves 12 after the ball races 20 and their balls 11 are assembled in the races 10 of the hub sleeve. The assembled unit is then screwed into the threaded portion 7 of the hub and when in their proper position, the pitch control mechanism is assembled.

The beveled gear 25 may be assembled on the spline portion 26 of the movable member'27 and the torsion spring fastened in the manner shown with its ends 29 and 30 secured to the casing 28 and the beveled gear 25 respectively. The entire actuating unit is then assembled on the hub bringing the teeth of the gear 25 incontact with the teeth of the split annuli l9.

The vent connections for the'annular chamber 32 with the exhaust of the engine may be effected in any suitable manner to conduct the scavenged fumes from the engine through the exhaust manifold and route them through the propeller blades to the reaction vents in the propeller tips.

After the blade roots have been assembled in their split annuli and secured by the sleeves 12, theymay be initially set to their normalposition and then fastened by the tapered lock rings 14. This is an adjustment which may be made without dismembering the blade assembly or the beveled annuli and without disturbing the antifriction bearings or removing the sleeves 8 and 9 from their threaded portions in the propeller hub.

Once this adjustment has been made, the torsion spring 29 will function to bias the blades to their normal position when there is-no force exerted by the hydraulic rotary actuator 27.

By constructing the hub as an integral casting in the manner herein disclosed, and by employing the propeller assembly units which are separably mounted on the hubstructure, a hub of minimum size and weight may be utilized for variable pitch propellers without any hazard of breakage.

It is also to be noted that by making provision for the venting of the scavenged fumes through integral passages, the hub structure is maintained in a very compact form and yet provides sufficient space for access to the parts by which it is mounted on the engine shaft.

Although one embodiment of the invention has been herein illustrated and described, it will be obvious to those skilled in the art that various modifications may be made in the details of constructicn without departing from the principles herein set forth.

I claim:

1. A variable pitch propeller mounting comprising an integrally formed casting having a spline socket for receiving a propeller drive shaft, a plurality of threaded openings disposed at right angles with said socket, a pair of hub sleeves fastened in screw thread engagement with said threaded openings for receiving the grooved anchorage abutments of the propeller blades, splitbeveled gear members adapted to be journalled in said hub sleeve and having grooves for interacting with the anchorage abutments of the propeller blade roots, said beveled gears having splined exterior surfaces, clamping means for mtimately engaging said surfaces to clamp the blade roots between the halves of said gear members, an actuating gear wheel having teeth engagement with said split bevel gear members for coordinating the pitch setting of the propeller blade, and an actuating mechanism disposed in said casting for actuating said pitch coordinating gear in response to a control.

2. Ina propeller hub structure, for mounting variable pitch propeller blades, 'a plurality of rotary members for clamping the anchorage abutments of the propeller blade roots comprising split annuli having radial grooves shaped complementary to the anchorage abutments of the blade roots, sleeve members disposed around said split annuli for securely clamping said split members in intimate contact with the blade roots and means for mounting said blades, annuli, and sleetvse members in the hub structure in assembled um 3. A hub structure for variable pitch propellers comprising an integral casting having a socket for mounting the hub on an engine shaft formed integrally therewith and having a plurality of rotary clamping means for anchoring the blade roots of the propellers, and means for mounting said blade root clamping members in said hub 1 of said casting, a pair of propeller blades mounted for rotary movement about their longitudinal axes in a plane transverse of said mounting socket, and apitch coordinating mechanism disposed in the front end of said hub and having gear teeth engagement with said rotary blade clamping means, said pitch coordinating mechanism and rotary blade anchorage members being adapted for assembly independently of each other posed within said'hub sleeves and adapted to cooperate with the split annuli to anchor the propeller blade roots therein.

I 6. A variable pitch propeller hub comprising an integral casting having a spline socket formed integrally at the rear end thereof for mounting the hub on the engine shaft, and having a relatively large opening at the front end thereof providing access to the interior of the hub, a

plurality of clamping members for engaging the blade roots of the propellers to adapt them for rotary movement in said hub, a cover for said end opening embodying actuating mechanism coacting with said blade clamping members for adjusting their pitch setting, and means for assembling said clamping members in the hub independently of the cover and hub assembly.

WALTER S. HOOVER.

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